From USA Today:
The handwritten manuscript titled “Quantum theory of the monatomic ideal gas” was dated December 1924. Considered one of Einstein’s last great breakthroughs, it was published in the proceedings of the Prussian Academy of Sciences in Berlin in January 1925.
High-resolution photographs of the 16-page, German-language manuscript and an account of its discovery were posted on the institute’s Web site.
“It was quite exciting” when a student working on his master’s thesis uncovered the delicate manuscript written in Einstein’s distinctive scrawl, said professor Carlo Beenakker. “You can even see Einstein’s fingerprints in some places, and it’s full of notes and markups from his editor.”
More here. [Thanks to Winfield J. Abbe.]